Influences of passivating elements on the corrosion and biocompatibility of super stainless steels

Biometals need high corrosion resistance since metallic implants in the body should be biocompatible and metal ion release should be minimized. In this work, we designed three kinds of super stainless steel and adjusted the alloying elements to obtain different microstructures. Super stainless steels contain larger amounts of Cr, Mo, W, and N than commercial alloys. These elements play a very important role in localized corrosion and, thus, their effects can be represented by the "pitting resistance equivalent number (PREN)." This work focused on the behavior which can arise when the bare surface of an implant in the body is exposed during walking, heavy exercise, and so on. Among the experimental alloys examined herein, Alloy Al and 316L stainless steels were mildly cytotoxic, whereas the other super austenitic, duplex, and ferritic stainless steels were noncytotoxic. This behavior is primarily related to the passive current and pitting resistance of the alloys. When the PREN value was increased, the passivation behavior in simulated body solution was totally different from that in acidic chloride solution and, thus, the Cr(2)O(3)/Cr(OH)(3) and [Metal oxide]/[Metal + Metal oxide] ratios of the passive film in the simulated body solution were larger than those in acidic chloride solution. Also, the critical current density in simulated body solution increased and, thus, active dissolution may induce metal ion release into the body when the PREN value and Ni content are increased. This behavior was closely related to the presence of EDTA in the simulated body solution.     

Comparison of treatment adherence between selective serotonin reuptake inhibitors and moclobemide in patients with social anxiety disorder

Objective

With respect to the pharmacotherapy of social anxiety disorder (SAD), it has been suggested that treatment duration is an important factor that can significantly predict responses. The present study aimed to compare the treatment adherence of SAD patients who were taking either SSRIs or reversible inhibitors of MAO-A (moclobemide) by measuring treatment duration and all-cause discontinuation rates of pharmacotherapy in a natural clinical setting.

Methods

We retrospectively analysed the data of 172 patients diagnosed with SAD. Depending on their medication, we divided the patients into two groups, SSRI (n=54) or moclobemide (n=118). The expected number of all-cause discontinuation every 2 weeks after starting treatment was calculated by life table survival methods. A multi-variable Cox proportional hazard regression was used to analyze the potential influence of explanatory variables.

Results

Treatment duration was significantly longer in the SSRI group [46.41±56.96, median=12.0 (weeks)] than in the moclobemide group [25.53±34.74, median=12.0 (weeks), Z=2.352, p=0.019]. Overall, all-cause discontinuation rates were significantly lower with SSRIs (81%) than moclobemide (96%, χ²=4.532, p=0.033).

Conclusion

The SSRI group had a longer treatment duration and lower all-cause discontinuation rate than moclobemide. Further, only the type of medication had a significant effect on all-cause discontinuation rates and therefore, we could predict better treatment adherence with the SSRIs in the treatment of SAD.     

Antireflux surgery normalizes cyclooxygenase-2 expression in squamous epithelium of the distal esophagus

BACKGROUND: In some patients GERD presents with heartburn and regurgitation symptoms but a relative paucity of endoscopic and clinical findings, while in others symptoms may be minor or absent yet there is significant mucosal damage on endoscopy including the presence of Barrett's esophagus. The initial injury of gastroesophageal reflux is to the squamous esophageal mucosa, but while substantial research has been devoted to determining which genes are involved in the progression of Barrett's to dysplasia and cancer, little is known about the gene expression alterations in the squamous mucosa of patients with reflux. We hypothesized that the expression of cyclooxygenase-2 (Cox-2) might be increased in the squamous esophageal mucosal of patients with reflux, and might be a molecular indicator of reflux injury. Further, we hypothesized that Cox-2 expression in the squamous mucosa would be reduced following the elimination of reflux with an antireflux operation. METHODS: Biopsies of the distal esophageal squamous mucosa were taken 3 cm above the squamocolumnar junction (SCJ) in 28 GERD patients before and after Nissen fundoplication. Following microdissection and RNA isolation, quantitative real-time PCR was used to measure Cox-2 gene expression in paraffin-embedded (N = 16) and fresh frozen (N = 12) tissue. Biopsies from patients (paraffin N = 15, frozen N = 14) with normal acid exposure and no evidence of mucosal injury were analyzed as controls. RESULTS: Median Cox-2 expression in the squamous epithelium from paraffin embedded biopsies in patients with reflux disease was significantly increased compared to controls (p = 0.04). The presence of esophagitis or Barrett's esophagus did not significantly alter the expression of Cox-2 compared to patients with nonerosive reflux disease (NERD). After antireflux surgery median Cox-2 expression values were significantly reduced (p = 0.0003) and were normalized to levels similar to controls without reflux (p = 0.74). Similar results were observed in the prospectively obtained fresh frozen tissue. CONCLUSIONS: Cox-2 gene expression is increased in the distal esophageal squamous mucosa of most patients with GERD, and the elevation was similar whether there was mucosal injury in the form of esophagitis or Barrett's or no visible mucosal injury. This suggests that increased Cox-2 expression may serve as a molecular marker of reflux disease. The increased Cox-2 expression in patients with reflux was usually normalized following antireflux surgery. These findings demonstrate for the first time that gene expression can be altered by surgical correction of reflux. Thus, in addition to symptom control and improvement in the quality of life, perhaps future studies assessing the efficacy of antireflux therapy should also focus on the impact of the therapy on gene expression in the esophageal squamous mucosa.     

Free-flap reconstruction of the scalp: donor selection and outcome

Wide, complex defects of the scalp caused by various insults always represent reconstructive challenges for surgeons. Our study group consisted of 18 patients (14 males and 4 females) with a mean age of 40.2 years. Nineteen free-tissue transfers were used to reconstruct the scalp defects. The selected cases included 8 latissimus dorsi muscle flaps, 3 latissimus dorsi myocutaneous flaps, 2 rectus abdominis muscle flaps, 3 omental flaps, 1 scapular flap, 1 radial forearm flap, and 1 groin flap. Twelve patients had acute or subacute wounds resulting from trauma or craniotomy, 4 had primary cancer, and 2 had neurofibromatosis. Commonly used recipient vessels were the superficial temporal artery and vein. No flap procedure had morbidity due to vessel compromise, and the overall flap success rate was thus 100%. No major donor-site morbidity was observed. All cases underwent primary closure of donor sites except for one receiving split-thickness skin grafting. In cases where muscle or omental free flaps covered skin grafts, patients were more satisfied because of increased durability and well-fitted wigs. We advocate variable free-tissue transfers for the reconstruction of large defects of the scalp related to the sizes, sites, and extents of the involvement.     

Estimating average glucose levels from glycated albumin in patients with end-stage renal disease

Purpose

In patients with diabetic end stage renal disease (ESRD), glycated albumin (GA) reflects recent glycemic control more accurately than glycated hemoglobin (HbA_1c). We evaluated the relationship between GA and average blood glucose (AG) level and developed an estimating equation for translating GA values into easier-to-understand AG levels.

Materials and Methods

A total of 185 ESRD patients, including 154 diabetic and 31 non-diabetic participants, were enrolled (108 hemodialysis, 77 peritoneal dialysis). Patients were asked to perform four-point daily self-monitoring of capillary blood glucose (SMBG) at least three consecutive days each week for four weeks. Serum levels of GA, HbA_1c and other biochemical parameters were checked at baseline, as well as at 4 and 8 weeks.

Results

Approximately 74.3±7.0 SMBG readings were obtained from each participant and mean AG was 169.1±48.2 mg/dL. The correlation coefficient between serum GA and AG levels (r=0.70, p<0.001) was higher than that of HbA_1c and AG (r=0.54, p<0.001). Linear regression analysis yielded the following equation: estimated AG (eAG) (mg/dL)=4.71×GA%+73.35, and with this formula, serum GA levels could be easily translated to eAG levels. Multivariate analysis revealed significant contributions of postprandial hyperglycemia (β=0.25, p=0.03) and serum albumin (β=0.17, p=0.04) in determining serum GA level, independent to other clinical parameters.

Conclusion

Compared to HbA_1c, serum GA levels were better correlated with AG levels. Using the estimating equation, an average blood glucose level of 155-160 mg/dL could be matched to a GA value of 18-19% in patients with ESRD.     

Use of long-term cultured embryoid bodies may enhance cardiomyocyte differentiation by BMP2

Purpose

Human embryonic stem cells (hESCs) can proliferate for a prolonged period and differentiate into cardiomyocytes in vitro. Recent studies used bone morphogenetic protein 2 (BMP2) to generate cardiomyocytes from hESCs, however, all those studies used early embryoid bodies (EBs) and did not retrieve cardiomyocytes with a high yield. In this study, we treated long-term cultured EBs with BMP2 in order to promote differentiation into cardiomyocytes from hESCs.

Materials and Methods

hESC lines, including SNUhES3 and SNUhES4, were used in this study. Undifferentiated hESC colonies were detached to form EBs and cultured for up to 30 days. These long-term cultured EBs were differentiated into cardiomyocytes in serum-containing media. In our protocol, BMP2 was applied for 5 days after attachment of EBs. Cardiac specific markers, beating of differentiated cells and electron microscopic (EM) ultrastructures were evaluated and analyzed.

Results

Compared to 10-day or 20-day EBs, 30-day EBs showed a higher expression level of cardiac specific markers, Nkx2.5 and α-myosin heavy chain (αMHC). Treatment of BMP2 increased expression of cardiac troponin (cTn) I and α-actinin when evaluated at 20 days after attachment of 30-day EBs. Beating of differentiated cells was observed from 7 to 20 days after attachment. Moreover, EM findings demonstrated fine structures such as Z bands in these differentiated cardiomyocytes. These long-term cultured EBs yielded cardiomyocytes with an efficiency of as high as 73.6% when assessed by FACS.

Conclusion

We demonstrated that the use of long-term cultured EBs may enhance differentiation into cardiomyocytes from hESCs when treated with BMP2.     

Use of 2.0 mini plate system as reduction plate

Fracture stabilization and reduction using temporary plates during intramedullary tibial nailing was introduced as a novel concept in fracture surgery by Benirschke et al. (Orthop Trans 18:1055–1056, 1995). The concept of temporary reduction using one-third tubular plates proved useful in aiding metaphyseal and periarticular fracture fixation also. However, planning the strategic location of final plate was the main limitation with this technique using one-third tubular plates. We used 2.0 mini plates as provisional reduction plates that solved the issue of planning and placement of plates. The main advantage of our technique is that the final definitive plate can be applied directly over the mini plates. Here, we will describe our technique using relevant fracture case in metaphyseal–periarticular location.     

Prognostic Role of Carcinoembryonic Antigen Level after Preoperative Chemoradiotherapy in Patients with Rectal Cancer

Background

The prognostic role of post-chemoradiotherapy (CRT) carcinoembryonic antigen (CEA) level is not clear. We evaluated the prognostic significance of post-CRT CEA level in patients with rectal cancer after preoperative CRT.

Methods

We reviewed 659 consecutive patients who underwent preoperative CRT and total mesorectal excision for non-metastatic rectal cancer. Patients were categorized into two groups according to post-CRT serum CEA level: low CEA (<?5 ng/mL) and high CEA (≥?5 ng/mL).

Results

Median post-CRT CEA level was 1.7 ng/mL (range, 0.1–207.0). A high post-CRT level was significantly associated with ypStage, ypT category, tumor regression grade, and pre-CRT CEA level. The 5-year overall survival rate of the 659 patients was 87.8% with a median follow-up period of 57.0 months (range, 1.4–176.4). When the post-CRT CEA groups were divided into groups according to pre-CRT CEA level, the 5-year overall survival rates were significantly different (P?<?0.001 and P?=?0.001, respectively). Post-CRT CEA level was an independent prognostic factor for overall survival. Multivariate analysis revealed that operation method, differentiation, perineural invasion, postoperative chemotherapy, tumor regression grade, and post-CRT CEA level were independent prognostic factors for overall survival.

Conclusion

The level of serum CEA after preoperative CRT was an independent prognostic factor for overall survival in patients with rectal cancer.

     

Chemoradiotherapy followed by surgery in rectal cancer: improved local control using a moderately high pelvic radiation dose

Background: To determine complete resection and sphincter preservation rates,down-staging, local control and survival associated with concurrentchemoradiotherapy (CCRT) using a moderately high pelvic radiationdose before surgery in rectal cancer. Methods: Fifty-seven patients with histologically proven adenocarcinomaof the mid to lower rectum were treated using preoperative CCRTand surgery. Median radiation dose to the pelvis was 5400 cGy(5040–5580 cGy). CCRT was administered during thefirst and fifth weeks of radiotherapy with bolus intravenous5-fluorouracil (5-FU) 400 mg/m²/day and leucovorin (LV)20 mg/m²/day for 5 days. Surgery was attempted 4–8weeks after completing preoperative CCRT. Post-operative chemotherapywas then added for up to four cycles of intravenous 5-FU andLV. Results: Toxicities during CCRT were generally mild and manageable: Grade1/2 anemia, 3.5%; Grade 1/2 leukopenia, 45.6%; Grade 3 leukopenia,3.5%; Grade 1/2 diarrhea, 22.8%; Grade 1/2 abdominal discomfort,7%; and perianal skin reaction, 5.3%. No late complication requiringsurgical intervention occurred. Complete surgical resectionwith a negative resection margin was achieved in 98.2% of patients,and the down-staging rate was 52.6% (30/57; 95% CI 39.6–65.6%).Complete pathologic response was obtained in 5.3% patients (3/57;95% CI 0-11.1%) and in other 2 patients only sporadic tumorcells nests were noted in surgical specimens. The sphincterpreservation rate was 77.2% (44/57; 95% CI 66.3–88.1%).Of 30 patients with tumors located within 5 cm from theanal verge, sphincter preservation was possible in 18 patients(60.0%; 95% CI 47.3–72.7%). With a median follow-up durationof 40 months, overall and disease-free survival (DFS) ratesover 3 years were 91.8% (95% CI 85.5–98.2%) and 79.7%(95% CI 71.2–88.2%), respectively. At univariate analysis,significant factors for DFS was LN involvement status (P = 0.024).Local and distant failure rates over the same period were 5.3and 21.1%, respectively. Conclusions: Preoperative CCRT produced encouraging down-staging rates andwas found to facilitate complete resection and sphincter savingin distal rectal cancer with acceptable toxicity. Further studiesare warranted using this moderately high radiation dose to thepelvis to improve the local control.     

Symptomatic perineural cyst after spontaneous subarachnoid hemorrhage: A case report

Rationale:Tarlov or perineurial cysts are nerve root lesions often found in the sacral region. Most perineural cysts (PCs) remain asymptomatic throughout a patient''s life. While their pathogenesis is still unclear, trauma resulting in hemorrhaging into subarachnoid space has been put forward as a possible cause of these cysts. Recently, we worked with a patient experiencing symptomatic PCs after spontaneous subarachnoid hemorrhage.Patient concerns:A 45-year-old man had a coil embolization procedure performed after being diagnosed with a subarachnoid hemorrhage from a ruptured anterior communicating artery. His symptoms were relieved after the procedure, but 7 days later he reported worsening pain in the left perineal area. The pain was intermittent at its onset and exacerbated by sitting, walking, and coughing.Diagnoses:Two weeks after the embolization procedure, a lumbar spine MRI revealed 2 PCs at the S1 and S2 level affecting the left S2 root with high signal intensity in T2 and T1 images, suggestive of bleeding within the cyst.Interventions:We operated using a posterior approach. Cyst fenestration was done after S1 laminectomy. We aspirated approximately 1 cc of old blood.Outcomes:His pain was relieved immediately after cyst removal and no neurologic deterioration occurred during the postoperative period.Lessons:Subarachnoid hemorrhage can be the source of the development of pain from asymptomatic PCs, making them symptomatic. Surgical extirpation is 1 treatment option for these symptomatic PCs.